Merge pull request #261 from openHPI/feature/la-dashboard

Add LA dashboard architecture

.babelrc

@@ -1,18 +0,0 @@
-{
-  "presets": [
-    ["env", {
-      "modules": false,
-      "targets": {
-        "browsers": "> 1%",
-        "uglify": true
-      },
-      "useBuiltIns": true
-    }]
-  ],
-
-  "plugins": [
-    "syntax-dynamic-import",
-    "transform-object-rest-spread",
-    ["transform-class-properties", { "spec": true }]
-  ]
-}

.postcssrc.yml

@@ -1,3 +0,0 @@
-plugins:
-  postcss-import: {}
-  postcss-cssnext: {}

.travis.yml

@@ -5,7 +5,7 @@ services:
 
 language: ruby
 rvm:
-  - 2.5.1
+  - 2.6.1
 cache:
   bundler: true
   yarn: true
@@ -27,7 +27,7 @@ before_install:
   - docker pull openhpi/co_execenv_python
   - docker pull openhpi/co_execenv_java
   - mkdir ~/geckodriver
-  - wget -O ~/geckodriver/download.tar.gz https://github.com/mozilla/geckodriver/releases/download/v0.23.0/geckodriver-v0.23.0-linux64.tar.gz
+  - wget -O ~/geckodriver/download.tar.gz https://github.com/mozilla/geckodriver/releases/download/v0.24.0/geckodriver-v0.24.0-linux64.tar.gz
   - tar -xvzf ~/geckodriver/download.tar.gz -C ~/geckodriver/
   - rm ~/geckodriver/download.tar.gz
   - chmod +x ~/geckodriver/geckodriver

Gemfile

@@ -17,8 +17,9 @@ gem 'pg'
 gem 'pry-byebug'
 gem 'puma'
 gem 'pundit'
-gem 'rails', '5.2.1.1'
+gem 'rails', '5.2.2'
 gem 'rails-i18n'
+gem 'i18n-js'
 gem 'ransack'
 gem 'rubytree'
 gem 'sass-rails'
@@ -31,12 +32,12 @@ gem 'tubesock', git: 'https://github.com/gosukiwi/tubesock', branch: 'patch-1' #
 gem 'faye-websocket'
 gem 'eventmachine', '1.0.9.1' # explicitly added, this is used by faye-websocket, newer versions might crash or
 gem 'nokogiri'
-gem 'd3-rails'
 gem 'webpacker'
 gem 'rest-client'
 gem 'rubyzip'
 gem 'mnemosyne-ruby'
 gem 'whenever', require: false
+gem 'rails-timeago'
 
 group :development, :staging do
   gem 'bootsnap', require: false

Gemfile.lock

@@ -10,49 +10,49 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    ZenTest (4.11.1)
+    ZenTest (4.11.2)
-    actioncable (5.2.1.1)
+    actioncable (5.2.2)
-      actionpack (= 5.2.1.1)
+      actionpack (= 5.2.2)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailer (5.2.1.1)
+    actionmailer (5.2.2)
-      actionpack (= 5.2.1.1)
+      actionpack (= 5.2.2)
-      actionview (= 5.2.1.1)
+      actionview (= 5.2.2)
-      activejob (= 5.2.1.1)
+      activejob (= 5.2.2)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.2.1.1)
+    actionpack (5.2.2)
-      actionview (= 5.2.1.1)
+      actionview (= 5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
       rack (~> 2.0)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.1.1)
+    actionview (5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.2.1.1)
+    activejob (5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
       globalid (>= 0.3.6)
-    activemodel (5.2.1.1)
+    activemodel (5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
-    activerecord (5.2.1.1)
+    activerecord (5.2.2)
-      activemodel (= 5.2.1.1)
+      activemodel (= 5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
       arel (>= 9.0)
-    activestorage (5.2.1.1)
+    activestorage (5.2.2)
-      actionpack (= 5.2.1.1)
+      actionpack (= 5.2.2)
-      activerecord (= 5.2.1.1)
+      activerecord (= 5.2.2)
       marcel (~> 0.3.1)
-    activesupport (5.2.1.1)
+    activesupport (5.2.2)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    addressable (2.5.2)
+    addressable (2.6.0)
       public_suffix (>= 2.0.2, < 4.0)
     airbrussh (1.3.1)
       sshkit (>= 1.6.1, != 1.7.0)
@@ -62,29 +62,28 @@ GEM
     autotest-rails (4.2.1)
       ZenTest (~> 4.5)
     bcrypt (3.1.12)
-    better_errors (2.5.0)
+    better_errors (2.5.1)
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)
       rack (>= 0.9.0)
     bindex (0.5.0)
     binding_of_caller (0.8.0)
       debug_inspector (>= 0.0.1)
-    bootsnap (1.3.2)
+    bootsnap (1.4.1)
       msgpack (~> 1.0)
     bootstrap-will_paginate (1.0.0)
       will_paginate
     builder (3.2.3)
-    bunny (2.12.0)
+    bunny (2.14.1)
       amq-protocol (~> 2.3, >= 2.3.0)
-    byebug (10.0.2)
+    byebug (11.0.0)
     capistrano (3.11.0)
       airbrussh (>= 1.0.0)
       i18n
       rake (>= 10.0.0)
       sshkit (>= 1.9.0)
-    capistrano-bundler (1.4.0)
+    capistrano-bundler (1.5.0)
       capistrano (~> 3.1)
-      sshkit (~> 1.2)
     capistrano-rails (1.4.0)
       capistrano (~> 3.1)
       capistrano-bundler (~> 1.1)
@@ -97,7 +96,7 @@ GEM
       capistrano (~> 3.7)
       capistrano-bundler
       puma (~> 3.4)
-    capybara (3.10.1)
+    capybara (3.14.0)
       addressable
       mini_mime (>= 0.1.3)
       nokogiri (~> 1.8)
@@ -105,7 +104,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (~> 1.2)
       xpath (~> 3.2)
-    carrierwave (1.2.3)
+    carrierwave (1.3.1)
       activemodel (>= 4.0.0)
       activesupport (>= 4.0.0)
       mime-types (>= 1.16)
@@ -113,10 +112,8 @@ GEM
       ffi (~> 1.0, >= 1.0.11)
     chronic (0.10.2)
     coderay (1.1.2)
-    concurrent-ruby (1.1.3)
+    concurrent-ruby (1.1.4)
     crass (1.0.4)
-    d3-rails (5.7.0)
-      railties (>= 3.1)
     database_cleaner (1.7.0)
     debug_inspector (0.0.3)
     diff-lcs (1.3)
@@ -126,34 +123,36 @@ GEM
       multi_json
     domain_name (0.5.20180417)
       unf (>= 0.0.5, < 1.0.0)
-    erubi (1.7.1)
+    erubi (1.8.0)
     eventmachine (1.0.9.1)
     excon (0.62.0)
     execjs (2.7.0)
-    factory_bot (4.11.1)
+    factory_bot (5.0.2)
-      activesupport (>= 3.0.0)
+      activesupport (>= 4.2.0)
-    factory_bot_rails (4.11.1)
+    factory_bot_rails (5.0.1)
-      factory_bot (~> 4.11.1)
+      factory_bot (~> 5.0.0)
-      railties (>= 3.0.0)
+      railties (>= 4.2.0)
-    faraday (0.15.3)
+    faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
     faye-websocket (0.10.7)
       eventmachine (>= 0.12.0)
       websocket-driver (>= 0.5.1)
-    ffi (1.9.25)
+    ffi (1.10.0)
     forgery (0.7.0)
-    globalid (0.4.1)
+    globalid (0.4.2)
       activesupport (>= 4.2.0)
     headless (2.3.1)
-    highline (2.0.0)
+    highline (2.0.1)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    i18n (1.1.1)
+    i18n (1.6.0)
       concurrent-ruby (~> 1.0)
+    i18n-js (3.2.1)
+      i18n (>= 0.6.6)
     ims-lti (1.2.2)
       builder
       oauth (>= 0.4.5, < 0.6)
-    jaro_winkler (1.5.1)
+    jaro_winkler (1.5.2)
     jbuilder (2.8.0)
       activesupport (>= 4.2.0)
       multi_json (>= 1.2)
@@ -161,9 +160,9 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    json (2.1.0)
+    json (2.2.0)
     jwt (2.1.0)
-    kramdown (1.17.0)
+    kramdown (2.1.0)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -179,25 +178,25 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
-    mimemagic (0.3.2)
+    mimemagic (0.3.3)
     mini_mime (1.0.1)
-    mini_portile2 (2.3.0)
+    mini_portile2 (2.4.0)
     minitest (5.11.3)
     mnemosyne-ruby (1.5.1)
       activesupport (>= 4)
       bunny
-    msgpack (1.2.4)
+    msgpack (1.2.7)
     multi_json (1.13.1)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
     net-scp (1.2.1)
       net-ssh (>= 2.6.5)
-    net-ssh (5.0.2)
+    net-ssh (5.1.0)
     netrc (0.11.0)
-    newrelic_rpm (5.4.0.347)
+    newrelic_rpm (6.1.0.352)
     nio4r (2.3.1)
-    nokogiri (1.8.5)
+    nokogiri (1.10.1)
-      mini_portile2 (~> 2.3.0)
+      mini_portile2 (~> 2.4.0)
     nyan-cat-formatter (0.12.0)
       rspec (>= 2.99, >= 2.14.2, < 4)
     oauth (0.5.4)
@@ -209,70 +208,74 @@ GEM
       rack (>= 1.2, < 3)
     pagedown-bootstrap-rails (2.1.4)
       railties (> 3.1)
-    parallel (1.12.1)
+    parallel (1.14.0)
-    parser (2.5.3.0)
+    parser (2.6.0.0)
       ast (~> 2.4.0)
-    pg (1.1.3)
+    pg (1.1.4)
     powerpack (0.1.2)
-    pry (0.12.0)
+    pry (0.12.2)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    pry-byebug (3.6.0)
+    pry-byebug (3.7.0)
-      byebug (~> 10.0)
+      byebug (~> 11.0)
       pry (~> 0.10)
+    psych (3.1.0)
     public_suffix (3.0.3)
     puma (3.12.0)
-    pundit (2.0.0)
+    pundit (2.0.1)
       activesupport (>= 3.0.0)
     rack (2.0.6)
-    rack-mini-profiler (1.0.0)
+    rack-mini-profiler (1.0.2)
       rack (>= 1.2.0)
     rack-proxy (0.6.5)
       rack
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (5.2.1.1)
+    rails (5.2.2)
-      actioncable (= 5.2.1.1)
+      actioncable (= 5.2.2)
-      actionmailer (= 5.2.1.1)
+      actionmailer (= 5.2.2)
-      actionpack (= 5.2.1.1)
+      actionpack (= 5.2.2)
-      actionview (= 5.2.1.1)
+      actionview (= 5.2.2)
-      activejob (= 5.2.1.1)
+      activejob (= 5.2.2)
-      activemodel (= 5.2.1.1)
+      activemodel (= 5.2.2)
-      activerecord (= 5.2.1.1)
+      activerecord (= 5.2.2)
-      activestorage (= 5.2.1.1)
+      activestorage (= 5.2.2)
-      activesupport (= 5.2.1.1)
+      activesupport (= 5.2.2)
       bundler (>= 1.3.0)
-      railties (= 5.2.1.1)
+      railties (= 5.2.2)
       sprockets-rails (>= 2.0.0)
-    rails-controller-testing (1.0.2)
+    rails-controller-testing (1.0.4)
-      actionpack (~> 5.x, >= 5.0.1)
+      actionpack (>= 5.0.1.x)
-      actionview (~> 5.x, >= 5.0.1)
+      actionview (>= 5.0.1.x)
-      activesupport (~> 5.x)
+      activesupport (>= 5.0.1.x)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
-    rails-i18n (5.1.2)
+    rails-i18n (5.1.3)
       i18n (>= 0.7, < 2)
       railties (>= 5.0, < 6)
-    railties (5.2.1.1)
+    rails-timeago (2.17.1)
-      actionpack (= 5.2.1.1)
+      actionpack (>= 3.1)
-      activesupport (= 5.2.1.1)
+      activesupport (>= 3.1)
+    railties (5.2.2)
+      actionpack (= 5.2.2)
+      activesupport (= 5.2.2)
       method_source
       rake (>= 0.8.7)
       thor (>= 0.19.0, < 2.0)
     rainbow (3.0.0)
-    rake (12.3.1)
+    rake (12.3.2)
-    ransack (2.1.0)
+    ransack (2.1.1)
       actionpack (>= 5.0)
       activerecord (>= 5.0)
       activesupport (>= 5.0)
       i18n
     rb-fsevent (0.10.3)
-    rb-inotify (0.9.10)
+    rb-inotify (0.10.0)
-      ffi (>= 0.5.0, < 2)
+      ffi (~> 1.0)
-    regexp_parser (1.2.0)
+    regexp_parser (1.3.0)
     rest-client (2.0.2)
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
@@ -291,7 +294,7 @@ GEM
     rspec-mocks (3.8.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.8.0)
-    rspec-rails (3.8.1)
+    rspec-rails (3.8.2)
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       railties (>= 3.0)
@@ -300,15 +303,16 @@ GEM
       rspec-mocks (~> 3.8.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.0)
-    rubocop (0.60.0)
+    rubocop (0.65.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.5, != 2.5.1.1)
       powerpack (~> 0.1)
+      psych (>= 3.1.0)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 1.4.0)
-    rubocop-rspec (1.30.1)
+    rubocop-rspec (1.32.0)
       rubocop (>= 0.60.0)
     ruby-progressbar (1.10.0)
     ruby_dep (1.5.0)
@@ -316,7 +320,7 @@ GEM
       json (~> 2.1)
       structured_warnings (~> 0.3)
     rubyzip (1.2.2)
-    sass (3.6.0)
+    sass (3.7.3)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -342,7 +346,7 @@ GEM
       actionpack (>= 3.1)
       railties (>= 3.1)
       slim (>= 3.0, < 5.0)
-    sorcery (0.12.0)
+    sorcery (0.13.0)
       bcrypt (~> 3.1)
       oauth (~> 0.4, >= 0.4.4)
       oauth2 (~> 1.0, >= 0.8.0)
@@ -355,31 +359,31 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
-    sshkit (1.18.0)
+    sshkit (1.18.2)
       net-scp (>= 1.1.2)
       net-ssh (>= 2.8.0)
     structured_warnings (0.3.0)
-    temple (0.8.0)
+    temple (0.8.1)
     thor (0.20.3)
     thread_safe (0.3.6)
-    tilt (2.0.8)
+    tilt (2.0.9)
     turbolinks (5.2.0)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    uglifier (4.1.19)
+    uglifier (4.1.20)
       execjs (>= 0.3.0, < 3)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.5)
-    unicode-display_width (1.4.0)
+    unicode-display_width (1.4.1)
     web-console (3.7.0)
       actionview (>= 5.0)
       activemodel (>= 5.0)
       bindex (>= 0.4.0)
       railties (>= 5.0)
-    webpacker (3.5.5)
+    webpacker (4.0.2)
       activesupport (>= 4.2)
       rack-proxy (>= 0.6.1)
       railties (>= 4.2)
@@ -411,7 +415,6 @@ DEPENDENCIES
   capybara
   carrierwave
   concurrent-ruby
-  d3-rails
   database_cleaner
   docker-api
   eventmachine (= 1.0.9.1)
@@ -420,6 +423,7 @@ DEPENDENCIES
   forgery
   headless
   highline
+  i18n-js
   ims-lti (< 2.0.0)
   jbuilder
   jquery-rails
@@ -435,9 +439,10 @@ DEPENDENCIES
   puma
   pundit
   rack-mini-profiler
-  rails (= 5.2.1.1)
+  rails (= 5.2.2)
   rails-controller-testing
   rails-i18n
+  rails-timeago
   ransack
   rest-client
   rspec-autotest
@@ -460,4 +465,4 @@ DEPENDENCIES
   whenever
 
 BUNDLED WITH
-   1.17.1
+   1.17.2

app/assets/javascripts/application.js

@@ -13,7 +13,10 @@
 //= require jquery_ujs
 //= require turbolinks
 //= require pagedown_bootstrap
-//= require d3
+//= require rails-timeago
+//= require locales/jquery.timeago.de.js
+//= require i18n
+//= require i18n/translations
 //
 // lib/assets
 //= require flash

app/assets/javascripts/base.js

@@ -23,3 +23,14 @@ $.fn.scrollTo = function(selector) {
     scrollTop: $(selector).offset().top - $(this).offset().top + $(this).scrollTop()
   }, ANIMATION_DURATION);
 };
+
+// Same as $.replaceWith, just returns the new element instead of the deleted one
+$.fn.replaceWithAndReturnNewElement = function(a) {
+    const $a = $(a);
+    this.replaceWith($a);
+    return $a;
+};
+
+// Disable the use of web workers for JStree due to JS error
+// See https://github.com/vakata/jstree/issues/1717 for details
+$.jstree.defaults.core.worker = false;

app/assets/javascripts/cable.js

@@ -0,0 +1,13 @@
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the `rails generate channel` command.
+//
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+
+}).call(this);

app/assets/javascripts/channels/la_exercises.js

@@ -0,0 +1,250 @@
+$(document).on('turbolinks:load', function() {
+    if ($.isController('exercises') && $('.teacher_dashboard').isPresent()) {
+
+        const exercise_id = $('.teacher_dashboard').data().exerciseId;
+        const study_group_id = $('.teacher_dashboard').data().studyGroupId;
+
+        const specific_channel = { channel: "LaExercisesChannel", exercise_id: exercise_id, study_group_id: study_group_id };
+
+
+        App.la_exercise = App.cable.subscriptions.create(specific_channel, {
+            connected: function () {
+                // Called when the subscription is ready for use on the server
+            },
+
+            disconnected: function () {
+                // Called when the subscription has been terminated by the server
+            },
+
+            received: function (data) {
+                // Called when there's incoming data on the websocket for this channel
+                if (data.type === 'rfc') {
+                    handleNewRfCdata(data);
+                } else if (data.type === 'working_times') {
+                    handleWorkingTimeUpdate(data.working_time_data)
+                }
+            }
+        });
+
+        function handleNewRfCdata(data) {
+            let $row = $('tr[data-id="' + data.id + '"]');
+            if ($row.length === 0) {
+                $row = $($('#posted_rfcs')[0].insertRow(0));
+            }
+            $row = $row.replaceWithAndReturnNewElement(data.html);
+            $row.find('time').timeago();
+            $row.click(function () {
+                Turbolinks.visit($(this).data("href"));
+            });
+        }
+
+        function handleWorkingTimeUpdate(data) {
+            const user_progress = data['user_progress'];
+            const additional_user_data = data['additional_user_data'];
+
+            const user = additional_user_data[additional_user_data.length - 1][0];
+            const position = userPosition[user.type + user.id]; // TODO validate: will result in undef. if not existent.
+            // TODO: Do update
+        }
+
+        const graph_data = $('#initial_graph_data').data('graph_data');
+        let userPosition = {};
+
+        drawGraph(graph_data);
+
+        function drawGraph(graph_data) {
+            const user_progress = graph_data['user_progress'];
+            const additional_user_data = graph_data['additional_user_data'];
+
+            function get_minutes (time_stamp) {
+                try {
+                    hours = time_stamp.split(":")[0];
+                    minutes = time_stamp.split(":")[1];
+                    seconds = time_stamp.split(":")[2];
+                    seconds /= 60;
+                    minutes = parseFloat(hours * 60) + parseInt(minutes) + seconds;
+                    if (minutes > 0){
+                        return minutes;
+                    } else{
+                        return parseFloat(seconds/60);
+                    }
+                } catch (err) {
+                    return 0;
+                }
+            }
+
+            function learners_name(index) {
+                return additional_user_data[additional_user_data.length - 1][index]["name"] + ", ID: " + additional_user_data[additional_user_data.length - 1][index]["id"];
+            }
+
+            function learners_time(group, index) {
+                if (user_progress[group] !== null && user_progress[group] !== undefined && user_progress[group][index] !== null) {
+                    return user_progress[group][index]
+                } else {
+                    return 0;
+                }
+            }
+
+            if (user_progress.length === 0) {
+                // No data available
+                $('#no_chart_data').removeClass("d-none");
+                return;
+            }
+
+            const margin = ({top: 20, right: 20, bottom: 150, left: 80});
+            const width = $('#chart_stacked').width();
+            const height = 500;
+            const users = user_progress[0].length; // # of users
+            const n = user_progress.length; // # of different sub bars, called buckets
+
+            let working_times_in_minutes = d3.range(n).map((index) => {
+                if (user_progress[index] !== null) {
+                    return user_progress[index].map((time) => get_minutes(time))
+                } else return new Array(users).fill(0);
+            });
+
+            let xAxis = svg => svg.append("g")
+                .attr("transform", `translate(0,${height - margin.bottom})`)
+                .call(d3.axisBottom(x).tickSizeOuter(0).tickFormat((index) => learners_name(index)));
+
+            let yAxis = svg => svg.append("g")
+                .attr("transform", `translate(${margin.left}, 0)`)
+                .call(d3.axisLeft(y).tickSizeOuter(0).tickFormat((index) => index));
+
+            let color = d3.scaleSequential(d3.interpolateRdYlGn)
+                .domain([-0.5 * n, 1.5 * n]);
+
+            let userAxis = d3.range(users); // the x-values shared by all series
+
+            // Calculate the corresponding start and end value of each value;
+            const yBarValuesGrouped = d3.stack()
+                .keys(d3.range(n))
+                (d3.transpose(working_times_in_minutes)) // stacked working_times_in_minutes
+                .map((data, i) => data.map(([y0, y1]) => [y0, y1, i]));
+
+            const maxYSingleBar = d3.max(working_times_in_minutes, y => d3.max(y));
+
+            const maxYBarStacked = d3.max(yBarValuesGrouped, y => d3.max(y, d => d[1]));
+
+            let x = d3.scaleBand()
+                .domain(userAxis)
+                .rangeRound([margin.left, width - margin.right])
+                .padding(0.08);
+
+            let y = d3.scaleLinear()
+                .domain([0, maxYBarStacked])
+                .range([height - margin.bottom, margin.top]);
+
+            const svg = d3.select("#chart_stacked")
+                .append("svg")
+                .attr("width", '100%')
+                .attr("height", '100%')
+                .attr("viewBox", `0 0 ${width} ${height}`)
+                .attr("preserveAspectRatio","xMinYMin meet");
+
+            const rect = svg.selectAll("g")
+                .data(yBarValuesGrouped)
+                .enter().append("g")
+                .attr("fill", (d, i) => color(i))
+                .selectAll("rect")
+                .data(d => d)
+                .join("rect")
+                .attr("x", (d, i) => x(i))
+                .attr("y", height - margin.bottom)
+                .attr("width", x.bandwidth())
+                .attr("height", 0)
+                .attr("class", (d) => "bar-stacked-"+d[2]);
+
+            svg.append("g")
+                .attr("class", "x axis")
+                .call(xAxis)
+                .selectAll("text")
+                .style("text-anchor", "end")
+                .attr("dx", "-.8em")
+                .attr("dy", ".15em")
+                .attr("transform", function(d) {
+                    return "rotate(-45)"
+                });
+
+            svg.append("g")
+                .attr("class", "y axis")
+                .call(yAxis);
+
+            // Y Axis Label
+            svg.append("text")
+                .attr("transform", "rotate(-90)")
+                .attr("x", (-height - margin.top + margin.bottom) / 2)
+                .attr("dy", "+2em")
+                .style("text-anchor", "middle")
+                .text(I18n.t('exercises.study_group_dashboard.time_spent_in_minutes'))
+                .style('font-size', 14);
+
+            // X Axis Label
+            svg.append("text")
+                .attr("class", "x axis")
+                .attr("text-anchor", "middle")
+                .attr("x", (width + margin.left - margin.right) / 2)
+                .attr("y", height)
+                .attr("dy", '-1em')
+                .text(I18n.t('exercises.study_group_dashboard.learner'))
+                .style('font-size', 14);
+
+            let tip = d3.tip()
+                .attr('class', 'd3-tip')
+                .offset([-10, 0])
+                .html(function(d, i, a) {
+                    return "<strong>Student: </strong><span style='color:orange'>" + learners_name(i) + "</span><br/>" +
+                        "0: " + learners_time(0, i) + "<br/>" +
+                        "1: " + learners_time(1, i) + "<br/>" +
+                        "2: " + learners_time(2, i) + "<br/>" +
+                        "3: " + learners_time(3, i) + "<br/>" +
+                        "4: " + learners_time(4, i);
+                });
+
+            svg.call(tip);
+
+            rect.on('mouseenter', tip.show)
+                .on('mouseout', tip.hide);
+
+            function transitionGrouped() {
+                // Show all sub-bars next to each other
+                y.domain([0, maxYSingleBar]);
+
+                rect.transition()
+                    .duration(500)
+                    .delay((d, i) => i * 20)
+                    .attr("x", (d, i) => x(i) + x.bandwidth() / n * d[2])
+                    .attr("width", x.bandwidth() / n)
+                    .transition()
+                    .attr("y", d => y(d[1] - d[0]))
+                    .attr("height", d => y(0) - y(d[1] - d[0]));
+            }
+
+            function transitionStacked() {
+                // Show all sub-bars on top of each other
+                y.domain([0, maxYBarStacked]);
+
+                rect.transition()
+                    .duration(500)
+                    .delay((d, i) => i * 20)
+                    .attr("y", d => y(d[1]))
+                    .attr("height", d => y(d[0]) - y(d[1]))
+                    .transition()
+                    .attr("x", (d, i) => x(i))
+                    .attr("width", x.bandwidth());
+            }
+
+            $('#no_chart_data').addClass("d-none");
+            transitionStacked();
+            // ToDo: Add button to switch using transitionGrouped();
+
+            buildDictionary(additional_user_data);
+        }
+
+        function buildDictionary(users) {
+            users[users.length - 1].forEach(function(user, index) {
+                userPosition[user.type + user.id] = index;
+            });
+        }
+    }
+});

app/assets/stylesheets/base.css.scss

@@ -113,3 +113,7 @@ span.caret {
     -webkit-transform: perspective(120px) rotateX(-180deg) rotateY(-179.9deg);
   }
 }
+
+.table-row-clickable {
+  cursor: pointer;
+}

app/assets/stylesheets/exercises.css.scss

@@ -84,6 +84,10 @@ div#chart_2 {
   background-color: #FAFAFA;
 }
 
+div#chart_stacked {
+  max-height: 500px;
+  background-color: #FAFAFA;
+}
 
 a.file-heading {
   color: black !important;
@@ -115,7 +119,7 @@ a.file-heading {
 .d3-tip:after {
   box-sizing: border-box;
   display: inline;
-  font-size: 10px;
+  font-size: 14px;
   width: 100%;
   line-height: 1;
   color: rgba(0, 0, 0, 0.8);
@@ -126,7 +130,7 @@ a.file-heading {
 
 /* Style northward tooltips differently */
 .d3-tip.n:after {
-  margin: -1px 0 0 0;
+  margin: -3px 0 0 0;
   top: 100%;
   left: 0;
 }

app/channels/application_cable/channel.rb

@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end

app/channels/application_cable/connection.rb

@@ -0,0 +1,30 @@
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+
+    def connect
+      self.current_user = find_verified_user
+    end
+
+    def disconnect
+      # Any cleanup work needed when the cable connection is cut.
+    end
+
+    private
+
+    def session
+      # `session` is not available here, so that we need to use `cookies.encrypted` instead
+      cookies.encrypted[Rails.application.config.session_options[:key]].symbolize_keys
+    end
+
+    def find_verified_user
+      # Finding the current_user is similar to the code used in application_controller.rb#current_user
+      current_user = ExternalUser.find_by(id: session[:external_user_id]) || InternalUser.find_by(id: session[:user_id])
+      if current_user
+        current_user
+      else
+        reject_unauthorized_connection
+      end
+    end
+  end
+end

app/channels/la_exercises_channel.rb

@@ -0,0 +1,16 @@
+class LaExercisesChannel < ApplicationCable::Channel
+
+  def subscribed
+    stream_from specific_channel
+  end
+
+  def unsubscribed
+    stop_all_streams
+  end
+
+  private
+  def specific_channel
+    reject unless StudyGroupPolicy.new(current_user, StudyGroup.find_by(id: params[:study_group_id])).stream_la?
+    "la_exercises_#{params[:exercise_id]}_channel_study_group_#{params[:study_group_id]}"
+  end
+end

app/controllers/concerns/lti.rb

@@ -168,6 +168,7 @@ module Lti
     end
     group.users |= [@current_user] # add current user if not already member of the group
     group.save
+    session[:study_group_id] = group.id
   end
 
   def set_embedding_options

app/controllers/concerns/submission_parameters.rb

@@ -16,7 +16,8 @@ module SubmissionParameters
       current_user_id = current_user.id
       current_user_class_name = current_user.class.name
     end
-    submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name) : {}
+    # The study_group_id might not be present in the session (e.g. for internal users), resulting in session[:study_group_id] = nil which is intended.
+    submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name, study_group_id: session[:study_group_id]) : {}
     reject_illegal_file_attributes!(submission_params)
     submission_params
   end

app/controllers/execution_environments_controller.rb

@@ -40,7 +40,7 @@ class ExecutionEnvironmentsController < ApplicationController
       FROM
         (SELECT user_id,
                 exercise_id,
-                CASE WHEN working_time >= '0:05:00' THEN '0' ELSE working_time END AS working_time_new
+                CASE WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0' ELSE working_time END AS working_time_new
          FROM
             (SELECT user_id,
                     exercise_id,

app/controllers/exercises_controller.rb

@@ -7,7 +7,7 @@ class ExercisesController < ApplicationController
 
   before_action :handle_file_uploads, only: [:create, :update]
   before_action :set_execution_environments, only: [:create, :edit, :new, :update]
-  before_action :set_exercise_and_authorize, only: MEMBER_ACTIONS + [:clone, :implement, :working_times, :intervention, :search, :run, :statistics, :submit, :reload, :feedback]
+  before_action :set_exercise_and_authorize, only: MEMBER_ACTIONS + [:clone, :implement, :working_times, :intervention, :search, :run, :statistics, :submit, :reload, :feedback, :study_group_dashboard]
   before_action :set_external_user_and_authorize, only: [:statistics]
   before_action :set_file_types, only: [:create, :edit, :new, :update]
   before_action :set_course_token, only: [:implement]
@@ -266,7 +266,7 @@ class ExercisesController < ApplicationController
   end
 
   def index
-    @search = policy_scope(Exercise).search(params[:q])
+    @search = policy_scope(Exercise).ransack(params[:q])
     @exercises = @search.result.includes(:execution_environment, :user).order(:title).paginate(page: params[:page])
     authorize!
   end
@@ -319,7 +319,7 @@ class ExercisesController < ApplicationController
   private :set_file_types
 
   def collect_set_and_unset_exercise_tags
-    @search = policy_scope(Tag).search(params[:q])
+    @search = policy_scope(Tag).ransack(params[:q])
     @tags = @search.result.order(:name)
     checked_exercise_tags = @exercise.exercise_tags
     checked_tags = checked_exercise_tags.collect{|e| e.tag}.to_set
@@ -343,7 +343,7 @@ class ExercisesController < ApplicationController
       @all_events = (@submissions + interventions).sort_by { |a| a.created_at }
       @deltas = @all_events.map.with_index do |item, index|
         delta = item.created_at - @all_events[index - 1].created_at if index > 0
-        if delta == nil or delta > 10 * 60 then 0 else delta end
+        if delta == nil or delta > StatisticsHelper::WORKING_TIME_DELTA_IN_SECONDS then 0 else delta end
       end
       @working_times_until = []
       @all_events.each_with_index do |_, index|
@@ -475,4 +475,15 @@ class ExercisesController < ApplicationController
     end
   end
 
+  def study_group_dashboard
+    authorize!
+    @study_group_id = params[:study_group_id]
+    @request_for_comments = RequestForComment.
+            where(exercise: @exercise).includes(:submission).
+            where(submissions: {study_group_id: @study_group_id}).
+            order(created_at: :desc)
+
+    @graph_data = @exercise.get_working_times_for_study_group(@study_group_id)
+  end
+
 end

app/controllers/external_users_controller.rb

@@ -27,7 +27,7 @@ class ExternalUsersController < ApplicationController
               score,
               id,
               CASE
-                  WHEN working_time >= '0:05:00' THEN '0'
+                  WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0'
                   ELSE working_time
               END AS working_time_new
        FROM

app/controllers/internal_users_controller.rb

@@ -60,7 +60,7 @@ class InternalUsersController < ApplicationController
   end
 
   def index
-    @search = InternalUser.search(params[:q])
+    @search = InternalUser.ransack(params[:q])
     @users = @search.result.includes(:consumer).order(:name).paginate(page: params[:page])
     authorize!
   end

app/controllers/proxy_exercises_controller.rb

@@ -33,7 +33,7 @@ class ProxyExercisesController < ApplicationController
   end
 
   def edit
-    @search = policy_scope(Exercise).search(params[:q])
+    @search = policy_scope(Exercise).ransack(params[:q])
     @exercises = @search.result.order(:title)
     authorize!
   end
@@ -44,14 +44,14 @@ class ProxyExercisesController < ApplicationController
   private :proxy_exercise_params
 
   def index
-    @search = policy_scope(ProxyExercise).search(params[:q])
+    @search = policy_scope(ProxyExercise).ransack(params[:q])
     @proxy_exercises = @search.result.order(:title).paginate(page: params[:page])
     authorize!
   end
 
   def new
     @proxy_exercise =  ProxyExercise.new
-    @search = policy_scope(Exercise).search(params[:q])
+    @search = policy_scope(Exercise).ransack(params[:q])
     @exercises = @search.result.order(:title)
     authorize!
   end
@@ -63,8 +63,8 @@ class ProxyExercisesController < ApplicationController
   private :set_exercise_and_authorize
 
   def show
-    @search = @proxy_exercise.exercises.search
+    @search = @proxy_exercise.exercises.ransack
-    @exercises = @proxy_exercise.exercises.search.result.order(:title) #@search.result.order(:title)
+    @exercises = @proxy_exercise.exercises.ransack.result.order(:title) #@search.result.order(:title)
   end
 
   #we might want to think about auth here

app/controllers/request_for_comments_controller.rb

@@ -15,7 +15,7 @@ class RequestForCommentsController < ApplicationController
     @search = RequestForComment
                   .last_per_user(2)
                   .with_last_activity
-                  .search(params[:q])
+                  .ransack(params[:q])
     @request_for_comments = @search.result
                                 .order('created_at DESC')
                                 .paginate(page: params[:page], total_entries: @search.result.length)
@@ -27,7 +27,7 @@ class RequestForCommentsController < ApplicationController
     @search = RequestForComment
                   .with_last_activity
                   .where(user_id: current_user.id)
-                  .search(params[:q])
+                  .ransack(params[:q])
     @request_for_comments = @search.result
                                 .order('created_at DESC')
                                 .paginate(page: params[:page])
@@ -40,7 +40,7 @@ class RequestForCommentsController < ApplicationController
                   .with_last_activity
                   .joins(:comments) # we don't need to outer join here, because we know the user has commented on these
                   .where(comments: {user_id: current_user.id})
-                  .search(params[:q])
+                  .ransack(params[:q])
     @request_for_comments = @search.result
                                 .order('last_comment DESC')
                                 .paginate(page: params[:page])
@@ -83,17 +83,10 @@ class RequestForCommentsController < ApplicationController
     authorize!
   end
 
-  # GET /request_for_comments/new
-  def new
-    @request_for_comment = RequestForComment.new
-    authorize!
-  end
-
   # GET /request_for_comments/1/edit
   def edit
   end
 
-  # POST /request_for_comments
   # POST /request_for_comments.json
   def create
     # Consider all requests as JSON
@@ -149,7 +142,7 @@ class RequestForCommentsController < ApplicationController
 
     # Never trust parameters from the scary internet, only allow the white list through.
     def request_for_comment_params
-      # we are using the current_user.id here, since internal users are not able to create comments. The external_user.id is a primary key and does not require the consumer_id to be unique.
+      # The study_group_id might not be present in the session (e.g. for internal users), resulting in session[:study_group_id] = nil which is intended.
       params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name)
     end
 

app/controllers/study_groups_controller.rb

@@ -4,17 +4,17 @@ class StudyGroupsController < ApplicationController
   before_action :set_group, only: MEMBER_ACTIONS
 
   def index
-    @search = StudyGroup.search(params[:q])
+    @search = StudyGroup.ransack(params[:q])
     @study_groups = @search.result.includes(:consumer).order(:name).paginate(page: params[:page])
     authorize!
   end
 
   def show
-    @search = @study_group.users.search(params[:q])
+    @search = @study_group.users.ransack(params[:q])
   end
 
   def edit
-    @search = @study_group.users.search(params[:q])
+    @search = @study_group.users.ransack(params[:q])
     @members = StudyGroupMembership.where(user: @search.result, study_group: @study_group)
   end
 

app/controllers/submissions_controller.rb

@@ -106,7 +106,7 @@ class SubmissionsController < ApplicationController
   end
 
   def index
-    @search = Submission.search(params[:q])
+    @search = Submission.ransack(params[:q])
     @submissions = @search.result.includes(:exercise, :user).paginate(page: params[:page])
     authorize!
   end
@@ -201,6 +201,8 @@ class SubmissionsController < ApplicationController
     save_run_output
 
     if @run_output.blank?
+      @raw_output ||= ''
+      @run_output ||= ''
       parse_message t('exercises.implement.no_output', timestamp: l(Time.now, format: :short)), 'stdout', tubesock
     end
 

app/helpers/action_cable_helper.rb

@@ -0,0 +1,30 @@
+module ActionCableHelper
+  def trigger_rfc_action_cable
+    # Context: RfC
+    if submission.study_group_id.present?
+      ActionCable.server.broadcast(
+        "la_exercises_#{exercise_id}_channel_study_group_#{submission.study_group_id}",
+        type: :rfc,
+        id: id,
+        html: (ApplicationController.render(partial: 'request_for_comments/list_entry',
+                                            locals: {request_for_comment: self})))
+    end
+  end
+
+  def trigger_rfc_action_cable_from_comment
+    # Context: Comment
+    RequestForComment.find_by(submission: file.context).trigger_rfc_action_cable
+  end
+
+  def trigger_working_times_action_cable
+    # Context: Submission
+    if study_group_id.present?
+      ActionCable.server.broadcast(
+          "la_exercises_#{exercise_id}_channel_study_group_#{study_group_id}",
+          type: :working_times,
+          working_time_data: exercise.get_working_times_for_study_group(study_group_id, user))
+    end
+  end
+end
+
+# TODO: Check if any user is connected and prevent preparing the data otherwise

app/helpers/statistics_helper.rb

@@ -1,5 +1,8 @@
 module StatisticsHelper
 
+  WORKING_TIME_DELTA_IN_SECONDS = 5.minutes
+  WORKING_TIME_DELTA_IN_SQL_INTERVAL = "'0:05:00'" # yes, a string with quotes
+
   def statistics_data
     [
         {

app/javascript/packs/application.js

@@ -13,7 +13,9 @@ import 'bootstrap/dist/js/bootstrap.bundle.min';
 import 'chosen-js/chosen.jquery';
 import 'jstree';
 import 'underscore';
+import 'd3'
 window._ = _; // Publish underscore's `_` in global namespace
+window.d3 = d3; // Publish d3 in global namespace
 
 // CSS
 import 'chosen-js/chosen.css';

app/models/comment.rb

@@ -1,8 +1,12 @@
 class Comment < ApplicationRecord
   # inherit the creation module: encapsulates that this is a polymorphic user, offers some aliases and makes sure that all necessary attributes are set.
   include Creation
+  include ActionCableHelper
+
   attr_accessor :username, :date, :updated, :editable
 
   belongs_to :file, class_name: 'CodeOcean::File'
   belongs_to :user, polymorphic: true
+
+  after_save :trigger_rfc_action_cable_from_comment
 end

app/models/exercise.rb

@@ -76,7 +76,7 @@ class Exercise < ApplicationRecord
         (SELECT user_id,
                 user_type,
                 score,
-                CASE WHEN working_time >= '0:05:00' THEN '0' ELSE working_time END AS working_time_new
+                CASE WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0' ELSE working_time END AS working_time_new
          FROM
             (SELECT user_id,
                     user_type,
@@ -90,6 +90,145 @@ class Exercise < ApplicationRecord
     "
   end
 
+  def study_group_working_time_query(exercise_id, study_group_id, additional_filter)
+    """
+    WITH working_time_between_submissions AS (
+      SELECT submissions.user_id,
+         submissions.user_type,
+         score,
+         created_at,
+         (created_at - lag(created_at) over (PARTITION BY submissions.user_type, submissions.user_id, exercise_id
+           ORDER BY created_at)) AS working_time
+      FROM submissions
+      WHERE exercise_id = #{exercise_id} AND study_group_id = #{study_group_id} #{additional_filter}),
+    working_time_with_deltas_ignored AS (
+      SELECT user_id,
+             user_type,
+             score,
+             sum(CASE WHEN score IS NOT NULL THEN 1 ELSE 0 END)
+                 over (ORDER BY user_type, user_id, created_at ASC)                 AS change_in_score,
+             created_at,
+             CASE WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0' ELSE working_time END AS working_time_filtered
+      FROM working_time_between_submissions
+    ),
+    working_times_with_score_expanded AS (
+      SELECT user_id,
+             user_type,
+             created_at,
+             working_time_filtered,
+             first_value(score)
+                         over (PARTITION BY user_type, user_id, change_in_score ORDER BY created_at ASC) AS corrected_score
+      FROM working_time_with_deltas_ignored
+    ),
+    working_times_with_duplicated_last_row_per_score AS (
+      SELECT *
+      FROM working_times_with_score_expanded
+      UNION ALL
+      -- Duplicate last row per user and score and make it unique by setting another created_at timestamp.
+      -- In addition, the working time is set to zero in order to prevent getting a wrong time.
+      -- This duplication is needed, as we will shift the scores and working times by one and need to ensure not to loose any information.
+      SELECT DISTINCT ON (user_type, user_id, corrected_score) user_id,
+                                                               user_type,
+                                                               created_at + INTERVAL '1us',
+                                                               '00:00:00' as working_time_filtered,
+                                                               corrected_score
+      FROM working_times_with_score_expanded
+    ),
+    working_times_with_score_not_null_and_shifted AS (
+      SELECT user_id,
+             user_type,
+             coalesce(lag(corrected_score) over (PARTITION BY user_type, user_id ORDER BY created_at ASC),
+                      0) AS shifted_score,
+             created_at,
+             working_time_filtered
+      FROM working_times_with_duplicated_last_row_per_score
+    ),
+    working_times_to_be_sorted AS (
+      SELECT user_id,
+             user_type,
+             shifted_score                                                          AS score,
+             MIN(created_at)                                                        AS start_time,
+             SUM(working_time_filtered)                                             AS working_time_per_score,
+             SUM(SUM(working_time_filtered)) over (PARTITION BY user_type, user_id) AS total_working_time
+      FROM working_times_with_score_not_null_and_shifted
+      GROUP BY user_id, user_type, score
+    ),
+    working_times_with_index AS (
+      SELECT (dense_rank() over (ORDER BY total_working_time, user_type, user_id ASC) - 1) AS index,
+             user_id,
+             user_type,
+             score,
+             start_time,
+             working_time_per_score,
+             total_working_time
+      FROM working_times_to_be_sorted)
+    SELECT index,
+       user_id,
+       user_type,
+       name,
+       score,
+       start_time,
+       working_time_per_score,
+       total_working_time
+    FROM working_times_with_index
+       JOIN external_users ON user_type = 'ExternalUser' AND user_id = external_users.id
+    UNION ALL
+    SELECT index,
+       user_id,
+       user_type,
+       name,
+       score,
+       start_time,
+       working_time_per_score,
+       total_working_time
+    FROM working_times_with_index
+       JOIN internal_users ON user_type = 'InternalUser' AND user_id = internal_users.id
+    ORDER BY index, score ASC;
+    """
+  end
+
+  def get_working_times_for_study_group(study_group_id, user = nil)
+    user_progress = []
+    additional_user_data = []
+    max_bucket = 4
+    maximum_score = self.maximum_score
+
+    if user.blank?
+      additional_filter = ''
+    else
+      additional_filter = "AND user_id = #{user.id} AND user_type = '#{user.class.name}'"
+    end
+
+    results = self.class.connection.execute(study_group_working_time_query(id, study_group_id, additional_filter)).each do |tuple|
+      if tuple['score'] <= maximum_score
+        bucket = tuple['score'] / maximum_score * max_bucket
+      else
+        bucket = max_bucket # maximum_score / maximum_score will always be 1
+      end
+
+      user_progress[bucket] ||= []
+      additional_user_data[bucket] ||= []
+      additional_user_data[max_bucket + 1] ||= []
+
+      user_progress[bucket][tuple['index']] = tuple["working_time_per_score"]
+      additional_user_data[bucket][tuple['index']] = {start_time: tuple["start_time"], score: tuple["score"]}
+      additional_user_data[max_bucket + 1][tuple['index']] = {id: tuple['user_id'], type: tuple['user_type'], name: tuple['name']}
+    end
+
+    if results.ntuples > 0
+      first_index = results[0]['index']
+      last_index = results[results.ntuples-1]['index']
+      buckets = last_index - first_index
+      user_progress.each do |timings_array|
+        if timings_array.present? && timings_array.length != buckets + 1
+          timings_array[buckets] = nil
+        end
+      end
+    end
+
+    {user_progress: user_progress, additional_user_data: additional_user_data}
+  end
+
   def get_quantiles(quantiles)
     quantiles_str = "[" + quantiles.join(",") + "]"
     result = self.class.connection.execute("""
@@ -180,7 +319,7 @@ class Exercise < ApplicationRecord
                     exercise_id,
                     max_score,
                     CASE
-                           WHEN working_time >= '0:05:00' THEN '0'
+                           WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0'
                            ELSE working_time
                     END AS working_time_new
              FROM   all_working_times_until_max ), result AS
@@ -274,7 +413,7 @@ class Exercise < ApplicationRecord
 
         FILTERED_TIMES_UNTIL_MAX AS
         (
-        SELECT user_id,exercise_id, max_score, CASE WHEN working_time >= '0:05:00' THEN '0' ELSE working_time END AS working_time_new
+        SELECT user_id,exercise_id, max_score, CASE WHEN working_time >= #{StatisticsHelper::WORKING_TIME_DELTA_IN_SQL_INTERVAL} THEN '0' ELSE working_time END AS working_time_new
         FROM ALL_WORKING_TIMES_UNTIL_MAX
         )
             SELECT e.external_id AS external_user_id, f.user_id, exercise_id, MAX(max_score) AS max_score, sum(working_time_new) AS working_time

app/models/request_for_comment.rb

@@ -1,5 +1,7 @@
 class RequestForComment < ApplicationRecord
   include Creation
+  include ActionCableHelper
+
   belongs_to :submission
   belongs_to :exercise
   belongs_to :file, class_name: 'CodeOcean::File'
@@ -10,6 +12,8 @@ class RequestForComment < ApplicationRecord
   scope :unsolved, -> { where(solved: [false, nil]) }
   scope :in_range, -> (from, to) { where(created_at: from..to) }
 
+  after_save :trigger_rfc_action_cable
+
     def self.last_per_user(n = 5)
       from("(#{row_number_user_sql}) as request_for_comments")
           .where("row_number <= ?", n)

app/models/study_group.rb

@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
 class StudyGroup < ApplicationRecord
-  has_many :study_group_memberships
+  has_many :study_group_memberships, dependent: :destroy
   # Use `ExternalUser` as `source_type` for now.
   # Using `User` will lead ActiveRecord to access the inexistent table `users`.
   # Issue created: https://github.com/rails/rails/issues/34531
   has_many :users, through: :study_group_memberships, source_type: 'ExternalUser'
-  has_many :submissions
+  has_many :submissions, dependent: :nullify
   belongs_to :consumer
 
   def to_s

app/models/submission.rb

@@ -1,6 +1,7 @@
 class Submission < ApplicationRecord
   include Context
   include Creation
+  include ActionCableHelper
 
   CAUSES = %w(assess download file render run save submit test autosave requestComments remoteAssess)
   FILENAME_URL_PLACEHOLDER = '{filename}'
@@ -20,6 +21,8 @@ class Submission < ApplicationRecord
   validates :cause, inclusion: {in: CAUSES}
   validates :exercise_id, presence: true
 
+  after_save :trigger_working_times_action_cable
+
   MAX_COMMENTS_ON_RECOMMENDED_RFC = 5
 
   def build_files_hash(files, attribute)

app/policies/application_policy.rb

@@ -25,6 +25,22 @@ class ApplicationPolicy
   end
   private :no_one
 
+  def everyone_in_study_group
+    study_group = @record.study_group
+    return false if study_group.blank?
+
+    users_in_same_study_group = study_group.users
+    return false if users_in_same_study_group.blank?
+
+    users_in_same_study_group.include? @user
+  end
+  private :everyone_in_study_group
+
+  def teacher_in_study_group
+    teacher? && everyone_in_study_group
+  end
+  private :teacher_in_study_group
+
   def initialize(user, record)
     @user = user
     @record = record

app/policies/exercise_policy.rb

@@ -3,8 +3,8 @@ class ExercisePolicy < AdminOrAuthorPolicy
     admin?
   end
 
-  def show?
+  [:show?, :study_group_dashboard?].each do |action|
-    admin? || teacher?
+    define_method(action) { admin? || teacher? }
   end
 
   [:clone?, :destroy?, :edit?, :statistics?, :update?, :feedback?].each do |action|

app/policies/study_group_policy.rb

@@ -3,8 +3,8 @@ class StudyGroupPolicy < AdminOnlyPolicy
     admin? || teacher?
   end
 
-  [:show?, :destroy?, :edit?, :update?].each do |action|
+  [:show?, :destroy?, :edit?, :update?, :stream_la?].each do |action|
-    define_method(action) { admin? || @user.teacher? && @record.users.include?(@user) }
+    define_method(action) { admin? || @user.teacher? && @record.present? && @record.users.include?(@user) }
   end
 
   class Scope < Scope

app/policies/submission_policy.rb

@@ -12,14 +12,8 @@ class SubmissionPolicy < ApplicationPolicy
     admin?
   end
 
-  def everyone_in_study_group
-    users_in_same_study_group = @record.study_groups.users
-    users_in_same_study_group.include? @user
-  end
-  private :everyone_in_study_group
 
-  def teacher_in_study_group
+  def show_study_group?
-    teacher? && everyone_in_study_group
+    admin? || teacher_in_study_group
   end
-  private :teacher_in_study_group
 end

app/views/exercises/external_users/statistics.html.slim

@@ -58,7 +58,7 @@ h1 = "#{@exercise} (external user #{@external_user})"
                 td =
                 td =
                 td = @working_times_until[index] if index > 0
-    p = t('.addendum')
+    p = t('.addendum', delta: StatisticsHelper::WORKING_TIME_DELTA_IN_SECONDS / 60)
     .d-none#wtimes data-working_times=ActiveSupport::JSON.encode(@working_times_until);
     div#progress_chart.col-lg-12
       .graph-functions-2

app/views/exercises/study_group_dashboard.html.slim

@@ -0,0 +1,37 @@
+- content_for :head do
+  // Force a full page reload, see https://github.com/turbolinks/turbolinks/issues/326.
+     Otherwise, code might not be highlighted correctly (race condition)
+  meta name='turbolinks-visit-control' content='reload'
+  = javascript_pack_tag('d3-tip', 'data-turbolinks-track': true)
+
+h1
+  = t('.live_dashboard')
+
+div.teacher_dashboard data-exercise-id="#{@exercise.id}" data-study-group-id="#{@study_group_id}"
+
+h4.mt-4
+  = t('.time_spent_per_learner')
+
+.d-none#initial_graph_data data-graph_data=ActiveSupport::JSON.encode(@graph_data);
+div.w-100#chart_stacked
+
+.d-none.badge-info.container.py-2#no_chart_data
+  i class="fa fa-info" aria-hidden="true"
+  = t('.no_data_yet')
+
+h4.mt-4
+  = t('.related_requests_for_comments')
+
+.table-responsive
+  table.table.table-hover.mt-4
+    thead
+      tr
+        th.text-center
+          i.mr-0 class="fa fa-lightbulb-o" aria-hidden="true" title = t('request_for_comments.solved')
+        th.text-center
+          i.mr-0 class="fa fa-comment" aria-hidden="true" title = t('request_for_comments.comments') align="center"
+        th.col-12 = t('activerecord.attributes.request_for_comments.question')
+        th = t('activerecord.attributes.request_for_comments.username')
+        th.text-nowrap = t('activerecord.attributes.request_for_comments.requested_at')
+    tbody#posted_rfcs
+      = render(partial: 'request_for_comments/list_entry', collection: @request_for_comments, as: :request_for_comment)

app/views/layouts/application.html.slim

@@ -5,6 +5,7 @@ html lang='en'
     meta name='viewport' content='width=device-width, initial-scale=1'
     title = application_name
     link href=asset_path('favicon.png') rel='icon' type='image/png'
+    = action_cable_meta_tag
     = stylesheet_pack_tag('application', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_pack_tag('stylesheets', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_link_tag('application', media: 'all', 'data-turbolinks-track': true)
@@ -12,6 +13,10 @@ html lang='en'
     = javascript_include_tag('application', 'data-turbolinks-track': true)
     = yield(:head)
     = csrf_meta_tags
+    = timeago_script_tag
+    script type="text/javascript"
+      | I18n.defaultLocale = "#{I18n.default_locale}";
+      | I18n.locale = "#{I18n.locale}";
   body
     - unless @embed_options[:hide_navbar]
       nav.navbar.navbar-dark.bg-dark.navbar-expand-md.mb-4.py-1 role='navigation'

app/views/request_for_comments/_list_entry.html.slim

@@ -0,0 +1,15 @@
+tr.table-row-clickable data-id=request_for_comment.id data-href=request_for_comment_path(request_for_comment)
+  td.p-2
+    - if request_for_comment.solved?
+      span.fa.fa-check.fa-2x.text-success aria-hidden="true"
+    - elsif request_for_comment.full_score_reached
+      span.fa.fa-check.fa-2x style="color:darkgrey" aria-hidden="true"
+    - else
+      = ''
+  td.text-center = request_for_comment.comments_count
+  - if request_for_comment.has_attribute?(:question) && request_for_comment.question.present?
+    td.text-primary = truncate(request_for_comment.question, length: 200)
+  - else
+    td.text-black-50.font-italic = t('request_for_comments.no_question')
+  td = request_for_comment.user
+  td = timeago_tag request_for_comment.created_at

app/views/request_for_comments/show.html.slim

@@ -9,6 +9,9 @@
     - testruns = Testrun.where(:submission_id => @request_for_comment.submission)
     = link_to_if(policy(user).show?, user.displayname, user)
     | | #{@request_for_comment.created_at.localtime}
+    - if @request_for_comment.submission.study_group.present? && policy(@request_for_comment.submission).show_study_group?
+      = ' | '
+      = link_to_if(policy(@request_for_comment.submission.study_group).show?, @request_for_comment.submission.study_group, @request_for_comment.submission.study_group)
   .rfc
     .description
       h5

app/views/submissions/show.html.slim

@@ -9,6 +9,7 @@ h1 = @submission
 
 = row(label: 'submission.exercise', value: link_to_if(policy(@submission.exercise).show?, @submission.exercise, @submission.exercise))
 = row(label: 'submission.user', value: link_to_if(policy(@submission.user).show?, @submission.user, @submission.user))
+= row(label: 'submission.study_group', value: link_to_if(policy(@submission.study_group).show?, @submission.study_group, @submission.study_group))
 = row(label: 'submission.cause', value: t("submissions.causes.#{@submission.cause}"))
 = row(label: 'submission.score', value: @submission.score)
 

app/views/user_mailer/send_thank_you_note.slim

@@ -1,5 +1,5 @@
 == t('mailers.user_mailer.send_thank_you_note.body',
         receiver_displayname: @receiver_displayname,
         link_to_comment: link_to(@rfc_link, @rfc_link),
-        author: @author.displayname,
+        author: @author,
         thank_you_note: @thank_you_note )

babel.config.js

@@ -0,0 +1,70 @@
+module.exports = function(api) {
+    var validEnv = ['development', 'test', 'production']
+    var currentEnv = api.env()
+    var isDevelopmentEnv = api.env('development')
+    var isProductionEnv = api.env('production')
+    var isTestEnv = api.env('test')
+
+    if (!validEnv.includes(currentEnv)) {
+        throw new Error(
+            'Please specify a valid `NODE_ENV` or ' +
+            '`BABEL_ENV` environment variables. Valid values are "development", ' +
+            '"test", and "production". Instead, received: ' +
+            JSON.stringify(currentEnv) +
+            '.'
+        )
+    }
+
+    return {
+        presets: [
+            isTestEnv && [
+                require('@babel/preset-env').default,
+                {
+                    targets: {
+                        node: 'current'
+                    }
+                }
+            ],
+            (isProductionEnv || isDevelopmentEnv) && [
+                require('@babel/preset-env').default,
+                {
+                    forceAllTransforms: true,
+                    useBuiltIns: 'entry',
+                    modules: false,
+                    exclude: ['transform-typeof-symbol']
+                }
+            ]
+        ].filter(Boolean),
+        plugins: [
+            require('babel-plugin-macros'),
+            require('@babel/plugin-syntax-dynamic-import').default,
+            isTestEnv && require('babel-plugin-dynamic-import-node'),
+            require('@babel/plugin-transform-destructuring').default,
+            [
+                require('@babel/plugin-proposal-class-properties').default,
+                {
+                    loose: true
+                }
+            ],
+            [
+                require('@babel/plugin-proposal-object-rest-spread').default,
+                {
+                    useBuiltIns: true
+                }
+            ],
+            [
+                require('@babel/plugin-transform-runtime').default,
+                {
+                    helpers: false,
+                    regenerator: true
+                }
+            ],
+            [
+                require('@babel/plugin-transform-regenerator').default,
+                {
+                    async: false
+                }
+            ]
+        ].filter(Boolean)
+    }
+};

bin/webpack

@@ -12,4 +12,8 @@ require "bundler/setup"
 
 require "webpacker"
 require "webpacker/webpack_runner"
-Webpacker::WebpackRunner.run(ARGV)
+
+APP_ROOT = File.expand_path("..", __dir__)
+Dir.chdir(APP_ROOT) do
+  Webpacker::WebpackRunner.run(ARGV)
+end

bin/webpack-dev-server

@@ -12,4 +12,8 @@ require "bundler/setup"
 
 require "webpacker"
 require "webpacker/dev_server_runner"
-Webpacker::DevServerRunner.run(ARGV)
+
+APP_ROOT = File.expand_path("..", __dir__)
+Dir.chdir(APP_ROOT) do
+  Webpacker::DevServerRunner.run(ARGV)
+end

config/application.rb

@@ -28,5 +28,7 @@ module CodeOcean
     config.autoload_paths << Rails.root.join('lib')
     config.eager_load_paths << Rails.root.join('lib')
     config.assets.precompile += %w( markdown-buttons.png )
+
+    config.action_cable.mount_path = '/cable'
   end
 end

config/cable.yml

@@ -1,10 +1,14 @@
 development:
-  adapter: async
+  adapter: postgresql
 
 test:
-  adapter: async
+  adapter: postgresql
+
+staging:
+  adapter: postgresql
 
 production:
-  adapter: redis
+  adapter: postgresql # redis
-  url: <%= ENV.fetch("REDIS_URL") { "redis://localhost:6379/1" } %>
+  # all other options below are only used for redis
-  channel_prefix: code_ocean_production
+  # url: <%= ENV.fetch("REDIS_URL") { "redis://localhost:6379/1" } %>
+  # channel_prefix: code_ocean_production

config/locales/de.yml

@@ -101,6 +101,7 @@ de:
         files: Dateien
         score: Punktzahl
         user: Autor
+        study_group: Lerngruppe
       study_group:
         name: Name
         external_id: Externe ID
@@ -347,6 +348,7 @@ de:
       implement: Implementieren
       test_files: Test-Dateien
       feedback: Feedback
+      study_group_dashboard: Live Dashboard
     statistics:
       average_score: Durchschnittliche Punktzahl
       final_submissions: Finale Abgaben
@@ -365,6 +367,13 @@ de:
       failure: Beim Übermitteln Ihrer Punktzahl ist ein Fehler aufgetreten. Bitte versuchen Sie es später erneut.
       full_score_redirect_to_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ein anderer Teilnehmer hat eine Frage zu der von Ihnen gelösten Aufgabe. Er würde sich sicherlich sehr über ihre Hilfe und Kommentare freuen.
       full_score_redirect_to_own_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ihre Frage ist damit wahrscheinlich gelöst? Falls ja, fügen Sie doch den entscheidenden Kniff als Antwort hinzu und markieren die Frage als gelöst, bevor sie das Fenster schließen.
+    study_group_dashboard:
+      live_dashboard: Live Dashboard
+      time_spent_per_learner: Verwendete Zeit pro Lerner
+      related_requests_for_comments: Zugehörige Kommentaranfragen
+      learner: Lerner
+      time_spent_in_minutes: benötigte Zeit in Minuten
+      no_data_yet: Bisher sind keine Daten verfügbar
     external_users:
       statistics:
         no_data_available: Keine Daten verfügbar.
@@ -373,7 +382,7 @@ de:
         score: Punktzahl
         tests: Unit Tests
         time_difference: 'Arbeitszeit bis hier*'
-        addendum: '* Differenzen von mehr als 10 Minuten werden ignoriert.'
+        addendum: '* Differenzen von mehr als %{delta} Minuten werden ignoriert.'
   proxy_exercises:
       index:
         clone: Duplizieren

config/locales/en.yml

@@ -101,6 +101,7 @@ en:
         files: Files
         score: Score
         user: Author
+        study_group: Study Group
       study_group:
         name: Name
         external_id: External ID
@@ -347,6 +348,7 @@ en:
       implement: Implement
       test_files: Test Files
       feedback: Feedback
+      study_group_dashboard: Live Dashboard
     statistics:
       average_score: Average Score
       final_submissions: Final Submissions
@@ -365,6 +367,13 @@ en:
       failure: An error occurred while transmitting your score. Please try again later.
       full_score_redirect_to_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Another participant has a question concerning the exercise you just solved. Your help and comments will be greatly appreciated!
       full_score_redirect_to_own_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Your question concerning the exercise is solved? If so, please share the essential insight with your fellows and mark the question as solved, before you close this window!
+    study_group_dashboard:
+      live_dashboard: Live Dashboard
+      time_spent_per_learner: Time spent per Learner
+      related_requests_for_comments: Related Requests for Comments
+      learner: Learner
+      time_spent_in_minutes: Time spent in Minutes
+      no_data_yet: No data available yet
     external_users:
       statistics:
         no_data_available: No data available.
@@ -373,7 +382,7 @@ en:
         score: Score
         tests: Unit Test Results
         time_difference: 'Working Time until here*'
-        addendum: '* Deltas longer than 10 minutes are ignored.'
+        addendum: "* Deltas longer than %{delta} minutes are ignored."
   proxy_exercises:
       index:
         clone: Duplicate

config/routes.rb

@@ -83,6 +83,7 @@ Rails.application.routes.draw do
       get :feedback
       get :reload
       post :submit
+      get 'study_group_dashboard/:study_group_id', to: 'exercises#study_group_dashboard'
     end
   end
 
@@ -151,4 +152,5 @@ Rails.application.routes.draw do
 
   post "/evaluate", to: 'remote_evaluation#evaluate', via: [:post]
 
+  mount ActionCable.server => '/cable'
 end

config/webpack/environment.js

@@ -18,6 +18,7 @@ environment.plugins.prepend('Provide', new webpack.ProvidePlugin({
         _: 'underscore',
         vis: 'vis',
         hljs: 'highlight.js',
+        d3: 'd3',
     })
 );
 

config/webpacker.yml

@@ -3,8 +3,11 @@
 default: &default
   source_path: app/javascript
   source_entry_path: packs
+  public_root_path: public
   public_output_path: packs
   cache_path: tmp/cache/webpacker
+  check_yarn_integrity: false
+  webpack_compile_output: false
 
   # Additional paths webpack should lookup modules
   # ['app/assets', 'engine/foo/app/assets']
@@ -13,7 +16,25 @@ default: &default
   # Reload manifest.json on all requests so we reload latest compiled packs
   cache_manifest: false
 
+  # Extract and emit a css file
+  extract_css: true
+
+  static_assets_extensions:
+    - .jpg
+    - .jpeg
+    - .png
+    - .gif
+    - .tiff
+    - .ico
+    - .svg
+    - .eot
+    - .otf
+    - .ttf
+    - .woff
+    - .woff2
+
   extensions:
+    - .mjs
     - .js
     - .sass
     - .scss
@@ -31,6 +52,9 @@ development:
   <<: *default
   compile: true
 
+  # Verifies that versions and hashed value of the package contents in the project's package.json
+  check_yarn_integrity: true
+
   # Reference: https://webpack.js.org/configuration/dev-server/
   dev_server:
     https: false
@@ -66,5 +90,8 @@ production:
   # Production depends on precompilation of packs prior to booting for performance.
   compile: false
 
+  # Extract and emit a css file
+  extract_css: true
+
   # Cache manifest.json for performance
   cache_manifest: true

db/migrate/20190213131802_add_indices_for_request_for_comments.rb

@@ -0,0 +1,6 @@
+class AddIndicesForRequestForComments < ActiveRecord::Migration[5.2]
+  def change
+    add_index :request_for_comments, :submission_id
+    add_index :request_for_comments, :exercise_id
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_11_29_093207) do
+ActiveRecord::Schema.define(version: 2019_02_13_131802) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -292,6 +292,8 @@ ActiveRecord::Schema.define(version: 2018_11_29_093207) do
     t.text "thank_you_note"
     t.boolean "full_score_reached", default: false
     t.integer "times_featured", default: 0
+    t.index ["exercise_id"], name: "index_request_for_comments_on_exercise_id"
+    t.index ["submission_id"], name: "index_request_for_comments_on_submission_id"
   end
 
   create_table "searches", force: :cascade do |t|
@@ -415,4 +417,5 @@ ActiveRecord::Schema.define(version: 2018_11_29_093207) do
     t.index ["user_type", "user_id"], name: "index_user_proxy_exercise_exercises_on_user_type_and_user_id"
   end
 
+  add_foreign_key "submissions", "study_groups"
 end

package.json

@@ -1,9 +1,10 @@
 {
   "dependencies": {
-    "@rails/webpacker": "3.5",
+    "@rails/webpacker": "4.0",
     "bootstrap": "^4.1.3",
     "bootswatch": "^4.1.3",
     "chosen-js": "^1.8.7",
+    "d3": "^5.9.1",
     "d3-tip": "^0.9.1",
     "font-awesome": "^4.7.0",
     "highlight.js": "^9.12.0",
@@ -17,7 +18,7 @@
     "webpack-merge": "^4.1.4"
   },
   "devDependencies": {
-    "webpack-dev-server": "2.11.2"
+    "webpack-dev-server": "3.2.1"
   },
   "scripts": {
     "webpack": "./bin/webpack",

postcss.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+    plugins: [
+        require('postcss-import'),
+        require('postcss-flexbugs-fixes'),
+        require('postcss-preset-env')({
+            autoprefixer: {
+                flexbox: 'no-2009'
+            },
+            stage: 3
+        })
+    ]
+};

provision.sh

@@ -5,9 +5,9 @@
 ######## VERSION INFORMATION ########
 
 postgres_version=10
-ruby_version=2.5.1
+ruby_version=2.6.1
-rails_version=5.2.1
+rails_version=5.2.2
-geckodriver_version=0.23.0
+geckodriver_version=0.24.0
 
 ########## INSTALL SCRIPT ###########
 

spec/support/factory_bot.rb

@@ -0,0 +1,4 @@
+require 'factory_bot'
+
+# Use "old" FactoryBot default to allow auto-creating associations for #build
+FactoryBot.use_parent_strategy = false